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Thermographic Testing. Vibrotech Reliability Services Limited. What is Thermography?. Infra Red Thermography is a technique for producing a visible image of invisible (to our eyes) infra red radiation emitted by objects due to their thermal conditions. Thermography. Objectives of Test
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Thermographic Testing Vibrotech Reliability Services Limited
What is Thermography? Infra Red Thermography is a technique for producing a visible image of invisible (to our eyes) infra red radiation emitted by objects due to their thermal conditions
Thermography Objectives of Test • To detect hot or cold area’s • To determine absolute temperature • To view Thermal profiles • To detect temperature loss
Thermography Infra Red is part of the Electromagnetic Spectrum • It travels in straight lines at the speed of light • The useful part is divided between Short and Long wavelengths • Use of the correct wavelength is essential
Test Equipment • Hand held portable camera • Battery Powered • Operating at correct wavelength • Range…..-20°c to +1500°c • Sensitivity…..0.1°c at 30°c • Real time display • Image Recording capability
Why Thermography? • Non Contact • Rapid Scanning • Data can be recorded in differing formats • Images produced are comprehensive & reliable • Is there a viable alternative?
Principles of Operation • Object radiates infra red radiation • Temperature difference • Differences are detected and displayed visually • Emissivity values must be observed
Advantages • Non Contact • Non Intrusive • Can work at a distance • Fast and Reliable • Portable • Convincing Results
Limitations • Non Intrinsically safe • There must be a temperature difference for certain surveys • Operator experience is essential • Filters may be needed for certain applications • Sensitivity and Resolution reduce with distance and angle of view
Electrical • Switch Gear • Fuse boxes • Cable runs • Electrical connectors • Insulation • Transformers
Electrical Connections Used for the detection of; • Corroded connections • Slack / loose connectors • Connectors at too high an operating temperature • Hot spots
Transformers • Electrical connections • Insulators • Thermal profile • Operating temperature • Liquid Level
Refractory Linings • Torpedo ladles • Boilers • Furnaces • Exhausts • Ducting • Kilns
Building Surveys Used to detect, • Lack of insulation • Cold air infiltration Draughts • Moisture traps • Hot / warm air escaping • Structural Integrity • Heating / Cooling
Building Surveys Moisture/Water Ingress • Leaking Roof • Bridged Cavity • Leaking pipes
Refinery & Petro-Chem • Vessel Surveys • Blockages • Defective lagging or insulation • Steam traps • Erosion / Corrosion
Process Plant The above Thermograms show how Thermography can be used as a very fast and effective maintenance tool. • The image on the right has a defective cylinder
Process Plant Thermography may be used for; • Corrosion surveys • Ensuring valve operation • Leaks • Blockages
Process Plant • Hot spots • Cold spots (Cryogenics) • Damaged or missing insulation • Tank levels
Miscellaneous • The detection of process or manufacturing faults • Can be used as a quality control tool